A stroke left Ballard unable to walk. He's also had a heart attack and he underwent a procedure to remove skin cancer from his neck. At 77, he's been in prison since 1993 for murder. He has 14 years left on his sentence.

Ballard is among the national surge in elderly inmates whose medical expenses are straining cash-strapped states and have officials looking for solutions, including early release, some possibly to nursing homes. Ballard says he's fine where he is.

"I'd be a burden on my kids," said the native Texan. "I'd rather be a burden to these people."

That burden is becoming greater as the American Civil Liberties Union estimates that elderly prisoners — the fastest growing segment of the prison population, largely because of tough sentencing laws — are three times more expensive to incarcerate than younger inmates.

The ACLU estimates that it costs about $72,000 to house an elderly inmate for a year, compared to $24,000 for a younger prisoner.

The federal Bureau of Justice Statistics reported that the number of men and women in state and federal prisons age 55 and older grew 76 percent between 1999 and 2008, the latest year available, from 43,300 to 76,400. The growth of the entire prison population grew only 18 percent in that period.

"We're reaping the fruits of bad public policy like Three Strikes laws and other mandatory minimum sentencing laws," said David C. Fathi, director of the ACLU National Prison Project in Washington, D.C. "One in 11 prisoners is serving a life sentence."

Washington has 2,495 inmates who are age 50 or older, the state's definition of elderly, according to information released after a public records request from The Associated Press. There are 270 inmates over the age of 65.

The infirm started arriving at the new assisted living facility at Coyote Ridge when it opened on Feb. 1.

The unit has a capacity of 74 inmates. To qualify, an inmate must be disabled and be considered a minimum security risk, prison superintendent Jeffrey Uttecht said.

The oldest inmate there is Ernest Tabor, 84, who was incarcerated for murder in 1997 and has 13 more years to serve. The average age in the assisted living unit is 59, a figure skewed slightly by three inmates in their 30s with disabilities.

Nearly all the inmates in the assisted living unit are in for murder or sex crimes, although a few are serving time for assault, drug or property crimes. Some were due to be released this year. Ballard is set for release in 2024.

The documents show the average age of a prison inmate in Washington has risen from 34.8 years in 2000 to 37.3 in 2010. The average is rising because of longer sentences, not because older people are being sent to prison, the state said.

The assisted living center is a unit in a much larger prison, which has two doctors for more than 2,000 total inmates. But the elderly prisoners tend to consume a big share of medical resources, including having two nurses assigned 24 hours a day, seven days a week, said health care manager Mary Jo Currey.

The assisted living prisoners need walkers, wheelchairs and lots of medications. Some experts suggest infirm prisoners could be more cheaply cared for in conventional nursing homes, as people over 50 rarely commit violent crime, Fathi said.

A visit to a prison ward for the elderly is an eye-opening experience, he said.

"Some were entirely bedridden," he said. "It looked like a nursing home with razor wire."

Many states are studying ways to reduce the number of elderly prisoners. New or expanded early release programs were adopted last year by 12 states and and the District of Columbia.

But a study released in April by the Vera Institute of Justice in New York City found the laws have rarely been used, in part because of political considerations and complicated reviews.

Early release for infirm inmates would be fine with Uttecht, the Coyote Ridge superintendent. But those prisoners need to be able to pay for the nursing care they need, so it doesn't happen often in Washington, he said.

"Usually it's for a terminal-type illness," he said.

Jane Parnell, who ran a special prison for the elderly in Yakima, Wash., that was closed last year because of high costs, said the public doesn't want these inmates released.

"A lot of them are sex offenders and fairly violent offenders," she said.

Parnell also questioned the necessity of the assisted living center, saying it is "more unusual than I think it should be." Many states just put elderly prisoners in the hospital ward, she said.

The assisted living unit at Coyote Ridge is inside the fence of the regular prison, but segregated from other units.

The building is one story and has wooden walls and wide doors to accommodate wheelchairs. There is a microwave oven, a shuffleboard table and a weight room in the common area.

Most inmates live in hospital ward style, with beds, desks and lockers. Sicker inmates have rooms with hospital beds.

Ballard lived much of his adult life in the Portland, Ore., area, where he worked on bridges, water towers and other tall structures.

His four kids bought his motorized wheelchair, an option not provided by the state. That allows him to work in the prison laundry, where he earns $52 a month. He doesn't like the prison food and purchases many of his meals from the prison store.

Ballard declined to discuss why he was in prison, but records show he was convicted in 1993 of killing his estranged second wife and her adult daughter.

He also watches news, travel and cooking programs on a small television. He sometimes plays bluegrass music on his guitar. His room has a sink and toilet and younger inmates are assigned to help him.

"Most will really help you," Ballard said. "It's not like in the movies, where there are a bunch of bullies out there."